Building a Better ELF

Modern mine finders are constantly merging old and new technology with outside-the-box thinking to create better, cheaper ways of exploring the ground under their feet.

Among those innovators is Arrawac Associates Inc. of Caledon, Ontario, and what President Andrew Dumyn has labelled the ELF/AFMAG survey system (Extremely Low Frequency/ Audio Frequency Magnetics), as the next generation of ground-level geomagnetic exploration.

Where today’s geomag surveys are heavy on equipment, labour and logistics, ELF offers a smaller, highly portable system that can deliver equal or better quality for a fraction of the cost.

“It’s a high-end technology that’s very inexpensive (compared to current methods),” says Aurora Geoscience President Gary Vivian of Yellowknife, who was the ELF’s first buyer in 2012.

Convinced of its potential for their northern clients, Aurora paid $100,000 in 2011, even though it had one big drawback — virtually no software had been developed to interpret its new data ELF.

Vivian assigned two of his geophysicists to the task, and this year hopes to complete an exhaustive test program to verify the ELF’s advantages, create their own proprietary software, and offer it to his clients across northern Canada and Alaska.

Global Lightning Harnessed

While a typical CSAMT survey requires a planeload of gear, fuel, camp supplies, and up to six staff, the new ELF needs only two surveyors who can easily carry the apparatus.   Cut lines are not necessary, and it can be used year-round. Daily production with a team of two is typically two to four line-kilometres depending on terrain, spacing and geomagnetic conditions, says an Aurora Geosciences technical paper.

The big advantage for explorers, says Vivian, is the elimination the electrical generator and wire array that crews laboriously set up and take down. The need for a camp, and potentially having to secure a land use permit can be considerably reduced.

The physics that makes this all possible has been known since the 1960s: the vast, natural energy shot into the planet by global lightning strikes (about 8 million every day) sends a continuous broadcast of very, very low frequency electrical waves throughout the earth’s crust. Crews don’t have to wait for a thunder storm to show up – lightning on the coastline of Peru creates enough low-level energy wave to be detected on Baffin Island. 

As the waves travel through different mineral or metallic zones and structures, they change course, depending on how conductive or resistive that zone is. What it maps is the disturbance in the flow of the current, or what geophysicists call the Tipper Vector, within a band width of 11 and 1440 hz.

In the field, an operator simply positions a 11-kilogram, orange plastic pod containing the detection antennae at stations along pre-programmed GPS points. At the push of a button, data collection starts, and the program tells the operator when it’s complete – usually within two minutes.

The pod is tethered with a 10-metre cable to the collection computer, housed in a sturdy case and carried by the second operator. Raw data can be read on site, in real time, and emailed to a central office for processing into two and three dimensional maps, giving accurate targets up to two kilometres deep.

The transformative leap is threefold: advanced technology in computing and detection systems; harnessing natural energy from lightning instead of artificially generated electrical pulses; and drastically reducing the cost and time.

Like any technology, ELF has its limitations: “noise” from nearby civil or industrial activity can impair the data, limiting application to more remote or isolated regions. And the lack of plug-and-play software, as yet, means buyers need to have the capacity to create their own.

Not yet on the market

Arrawac’s Andrew Dumyn is neither a geologist or geophysicist, but has a 30 year-year career in marshalling large scale survey programs and the technology behind them. That led him look to for a better way to get better, cheaper ground surveys.

He teamed up with Russian-born geophysicist Petr Kuzmin, who had recently left the Canadian firm Geotech Inc. of Aurora, Ontario, to develop something new.

He credits Kuzmin with the genius behind the new ELF system’s breakthrough in miniaturizing equipment and harnessing existing energy from global lightning. Together, they created the prototype system, which is owned by Kuzmin and licensed to Dumyn as the exclusive distributor.

Dumyn explains that French and Russian scientists actually created the foundation of geomagnetic exploration in the 1940s, and a commercial, analog-based systems was in play by the 1960s. But it was primitive, lacking the computing power to process data, says Dumyn, and it went dormant until the 1990’s when Geotech applied nascent digital technology, and revived the idea.

Dumyn claims it is “one of the most significant geophysical advancement in the past 10 years for mineral exploration because it can see things that other systems can’t… in real time. It can map structure and alteration up to a depth of two kilometres.”

Based in Caledon Ontario, Dumyn is carefully parcelling out ELF/AFMAG technology to trusted companies which, like Aurora, are beta testing it and creating their own software. He has commissioned his own 3D inversion program.

He does not have a website, and is not yet launching extensive marketing until testing is complete. “We need to prove how well this technology works, and this is the year we’ll have the case studies to back it up.”

Transformative Technology

Vivian’s team has tested the system against several known properties – gold, base metal and geothermal – with extensive drill logs, to confirm that what it reads is actually what’s in the ground.

They’re very satisfied with the results.

“The instrument works,” says Vivian. “It’s the processing of the data to provide the client with a conceptual model of what it’s showing you – this is the challenge.”

Aurora geophysicist Franz Dzuiba, along with geologist Dave Hilde of their Whitehorse office, are developing that software.

“This unit is lightweight and portable,” says Dzuiba. “So logistically speaking, the advantages to running this survey are huge… now what we’re looking at will this tell us more (than earlier methods)? All indications are that it is.

“The easiest deposits have been picked off the tree,” he adds. “We’re looking for a tool that will find more deposits… hidden from geologists and traditional geophysical methods.”

Vivian, whose company has operated across the Arctic since 1982, says it’s “transformative technology” that he predicts will be rapidly adopted as “a first-pass system – a very quick and economical way to look at your ground package”.

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